Are most environmental issues local problems or global problems? How can or will this affect the way we try to solve these issues?

How are environmental issues becoming more complex?

What about the history of environmental studies can inform us about our current environmental issues? Why is it important to understand the past to help solve current and future environmental problems?

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

this is more of a statement than a question. is there answers to go along with this, or is it opinion based?

1)

i))the process of preparing food by green plants in the presence of sunlight is called photosynthesis.

ii) leaf is the site for photosynthesis.

iii) it takes place as,

6h2o+6co2=c6h12o6+602